there is a nexus mod here that changes the difficulty of survival:
http://www.nexusmods.com/fallout4/mods/333/?
and on the screen you can see that both the original 'very hard' and the original 'survival' have 0,5x for damage dealt and 2x for damage received
is that true? oO
is the only difference from very hard to survival the time that a stimpack needs to heal you?
I assumed survival would be something like 0,25x and 4x °_°